Light field capture devices (also referred to as “light field image data acquisition devices” or “light field cameras”) are defined herein as any devices that are capable of capturing light field data, optionally processing light field data, optionally accepting and acting upon user input, and/or optionally displaying or otherwise outputting images and/or other types of data.
Light field capture devices such as plenoptic cameras may capture light field data using any suitable method for doing so. One example of such a method includes, without limitation, using a microlens array (MLA) disposed between a main imaging lens and an image sensor (e.g., a CCD or CMOS sensor) as described in Ng et al., Light field photography with a hand-held plenoptic capture device, Technical Report CSTR 2005-02, Stanford Computer Science.
In most MLA-based plenoptic cameras, the MLA is disposed within the optical path, in front of and close to (or in contact with) the image sensor. The main lens collects light from the scene and projects this onto the MLA and image sensor combination (also known as the light field sensor). Each lens of the MLA images a portion of the exit pupil image from the main lens onto the image sensor as a series of disk images. Each lens of the MLA records a slightly different portion of the exit pupil of main lens. This difference in the projected MLA disk images can be used to compute the angular direction of the light rays at each pixel location. Optically this system is equivalent to a sub-aperture array based plenoptic camera.
In an MLA-based plenoptic camera, the MLA is usually attached to the image sensor surface at a fixed distance that is optimized to achieve the best spatial and angular resolution for the application of the light field camera. The MLA can be designed with different microlens pitches and focal distances to enable higher spatial resolution or to enable higher angular resolution.
However, existing MLA-based plenoptic cameras are generally unable to provide dual modes wherein the camera alternatively functions as either a light field camera or a conventional 2D camera.